Induction of micronuclei in the domestic cat (Felis domesticus) peripheral blood by colchicine and cytosine-arabinoside.

One advantage of bioassays over other kinds of tests is the processing or metabolism of the compound by the organism. In a previous work, in which we reported the number of micronucleated erythrocytes (MNE) in the peripheral blood of 35 species, the cat was one of the species with the highest number of micronuclei (MN). Cats have a low level of circulating polychromatic erythrocytes (PCE), i.e. 0.05%, which is much lower than in the laboratory mouse, but higher than in species such as cows, donkeys, sheep, goats and horses. Thus, MN were scored in total blood erythrocytes. In the present work, we assess the cat as a test system for MN induction. Three doses of a colchicine-cytosine arabinoside mixture were administered to young cats during 4 days; then, the numbers of MNE in blood collected before the first injection and 48 and 96 h later were compared. The number of MNE increased with time, reaching the highest values in the samples taken 96 h after the administration of the micronucleogenic agents.